As a radio access scheme, LTE (Long Term Evolution) which is standardized by the 3GPP (3rd Generation Partnership Project), a standardization body for radio communication systems, adopts OFDMA (Orthogonal Frequency Division Multiple Access) for a downlink and adopts SC-FDMA (Single Carrier-Frequency Division Multiple Access) for an uplink.
Also, the LTE mainly adopts FDD (Frequency Division Duplex) as a duplex scheme for separating the downlink from the uplink. When the FDD is adopted, a frequency band of the uplink is different from that of the downlink.
The 3GPP proposes a method for a situation where a radio base station (which is referred to as “eNB” in the 3GPP) is newly installed, the method enabling automatic setting of the newly-installed base station to be made by connecting the newly-installed base station to a network via a cable, and by powering on the newly-installed base station.
A technology of automatically optimizing performances such as transmission capacity, transmission delay, and frequency-and-power usage efficiency of a radio communication system as described above is called as SON (Self Organized Network). With the SON, measurement or setting in situ can be automated without requiring manual operations when a radio base station is installed or maintained.
As one function of the SON, there is proposed a method in which a radio terminal (which is referred to as “UE” in the 3GPP) performing a radio communication with a radio base station reports a result of measuring a radio signal received from a base station neighboring the radio base station, and the radio base station knows an operational status of the neighboring base station (see, non-patent literature 1).